The Knowles campaign did not submit a form for radio and television commercials that declares whether the commercial airs an opponent's name and pledges that the candidate's picture and name will be clearly shown.

The requirement, an addition since campaign finance reforms in 2002, allows candidates to buy commercials at a discount starting 45 days before the primary. Alaska's primary is on Aug. 24, which meant the paperwork had to be filed at the stations airing the commercials starting July 10.

On Friday, an attorney for the Murkowski campaign sent a letter to seven television stations asking them to stop airing Knowles' ads.

"The Murkowski campaign is confident that your station does not intend to violate either the Federal Communications Act or the Federal Election Act," attorney Tim McKeever wrote.

The stations have asked for a ruling by the Federal Communications Commission.

If the FCC sustains the complaint, Knowles could have to pay additional funds for television ads.